Get printable Foot height table(.pdf)
As I mentioned on our About Us Page, we have a Logan Pro Joiner (Model F300-2) for nailing our frames together. There are four different things on it that one must adjust before using it. But there are only two important parameters, moulding width and moulding thickness, that are used to make those adjustments. To make your life easier, I made three new scales to put on your joiner for the adjustments that depend on the moulding width.
I will discuss how to apply these scales to your joiner and how to use them as we look at each of the adjustments in more detail. I will discuss them in the same order they were introduced in the manual.
V-nail Slider Block Spacing
The Old Scale
The scale on the slider measures the gap between the two V-nails (except the reading on that scale is always ⅜” larger than the actual distance). The manual tells you to set the slider block to match the reading on the vise scale, which measures the width of the moulding across its bottom. This width is the total moulding width minus the width of the rabbet that holds in the glass and is the width that matters in this case. We will call this measurement “W”. They claim that if you do set the V-nail slider to that number, each V-nail will be ¼” from the nearest end of the miter joint. That is not true.
which reduces to
by dividing the whole expression by the square root of two, the average distance to the nearest edge would be
The New Scale
The numbers on my new scale (labeled “A” in Figure 1 and “Gap scale” in Figure 2 above) represent the moulding width W, not the gap between nails. In addition, following my scales will put the V-nails 25% of the joint length in from each end, which is also 25% of the moulding width in from each edge of the moulding. I do this because if I were using only one V-nail I would put it in the center. For two V-nails, I conceptually divide the moulding in half and put a V-nail in the center of each half. If the moulding were wide enough to require three V-nails, I would divide the moulding into thirds and put the nail in the center of each third. Is there a structural engineer in the house or someone that knows a better place to position the V-nails? I’m listening.
Attaching the scale
If you download the JPEG (.jpg) file of the scales (click the link just below the title of this article), you can print them either on plain paper or maybe even a 2″ by 4″ label. The red lines and numbers (shown in Figure 2) correspond to the existing scale. After printing, you should compare the distances between a few of the red lines to the same distances on the old scale be sure your printer/software didn’t arbitrarily change the size of the print. Then cut along the blue lines. The black lines and numbers represent the bottom moulding width (W). For the slider block or gap scale, place the edge of the sliding V-nail block on the ¾” mark on the existing scale. Then place my scale on the opposite side of the slider so that the red ¾” mark is lined up with that same edge of the block (as shown in Figure 3).
Using the scale
To use these scales to press two V-nails into the moulding, just put the V-nail block on W, as you read it from the vise scale. Then do the same to the V-nail Corner Spacing Stop and the Lever Adjustment Block (both discussed below). Then make all other adjustments as prescribed in the manual and lower the pressure foot onto the moulding.
If you needed to press three V-nails, you would press the outer two by following the above instructions to adjust the components at all three scales to a value 2/3 of W. For example, if the measured moulding width was 3″, you would adjust all W settings to 2″. Press the V-nails. Then put the third V-nail into the sliding nail holder only (leaving the fixed nail holder empty). Set the gap (a.k.a. slider block spacing) and the pressure foot placement for 4/3 × W or 4″, leaving the other adjustments the same. Press the last nail.
If you would prefer to set the V-nails as you were before, or even if you would prefer to put them where Logan said you were putting them before, then an additional set of scales could easily be made using the moulding width as the setting instead of actual nail distances, so you would only have to read the vise scale and set everything automatically, without further calculations. Although simplicity was the motivation for this effort, having multiple alternative scales is beyond the scope of this article. But if you need help with that, let me know.
V-nail Corner Spacing
This scale (labeled “B” in Figure 1) is located on the back of the left slider guide (as you face the joiner from the front). The original scale goes from ¼” to ¾” in ⅛” increments, which is a slightly larger range than the V-nail Corner Spacing Stop (on the back end of the right guide) can use. That scale shows the distance the outside V-nail will be in from the corner of the moulding, but it reads more than 1/16” smaller than the actual distance. For example, the position of the V-nail slider in Figure 4 will put the outer V-nail ½” from the corner of the moulding.
My scale would go to the right of the original scale so that both scales are still available. After placing the scale, measure the distance between the ¼” mark on the old scale and the red ¼” mark on the new scale. That is the distance the arrow should be placed from the back end of the slider. It should be ⅛” above the bottom edge of the slider so it can be seen above the slider guide.
Pressure Foot Placement
For simple moulding profiles that do not require the black moulding spacer, I created a scale (labeled “C” in Figure 1) based on moulding width W to help center the pressure foot over the moulding.
Cut out the Pad scale (see Figure 2) and place it to the left of the lever adjustment block (the same side as the Pro Joiner label, as shown in Figure 5 above) so that the red edge line is on the edge of the top plate, as shown in Figure 1. To place the arrow, slide the lever adjustment block all the way back (in Figure 5, that would be to the left). Then place the arrow above the edge of the top plate.
When setting up the joiner, put the arrow over W. It is that simple. But our 1½” stretcher moulding, for which W is 1″, has a ridge along the outer edge of the moulding that is ⅜” wide. The simplest way to handle that is to pretend there is a symmetrical ⅜” wide ridge on the other edge of the moulding; add ⅜” to W, and set the pressure foot to that 1⅜” value. On the other hand, if that moulding had an obstacle only on the inner edge instead, you would subtract ⅜” from W, and set the pressure foot to the resulting ⅝” value, in the case of our example.
Adjust Foot Height
This is the setting based on moulding thickness instead of W. The size of the V-nail used is also a factor, but that is also based on moulding thickness. Unfortunately, I have not yet found a good way to attach a scale for this adjustment. Just follow the instructions in the manual; they are pretty straight forward. The lever handle should be just a little above horizontal when the moulding first contacts the V-nails, and should be the same angle below horizontal when the lever handle bottoms out. The precise angle is not important here.
Below is a table that relates the moulding thickness to the number of threads that should be exposed above the lever height wheel (there are twelve threads per inch on the lever shaft). The table is preliminary, but you could download the .pdf file (look just below the title of this article) and you could even attach it to the top plate of the joiner if it is helpful. After you improve it, please send me a copy.
Odds and Ends
We haven’t ever deliberately stacked V-nails, as discussed on Page 6 of the manual, but we have tried a different brand of V-nail that is longer than the largest Logan. We use the AMP (a Fletcher Company) 15mm Mitre-Mite V-nail (their longest), as mentioned in Figure 6, for our 1½” stretcher moulding. It works well on our Logan joiner.
We used to apply glue to the miter joint and then immediately use the joiner to put our frames together. After the beginner’s luck wore off, we noticed that the joints weren’t as tight as we would have liked. Then I stumbled onto a couple of websites that suggested gluing the frame together first using a band clamp and then V-nailing the corners after the glue dries. One of those references was an old article on the Logan Graphics blog. We haven’t had any problem with that since.
That’s All, Folks
That should about cover it. If you have any questions, or shortcuts, or any other suggestions for improvement, let me know in the comment section below. And if not, then thanks for listening.